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Author Topic: Another question about light...  (Read 1794 times)

paul.fr

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Another question about light...
« on: 11/03/2007 22:23:18 »
Yes i know, another question about light....

the question is this: When i have new batteries in my bicycle lamps the beam is a nice white light, when the batteries start to run down the beam is more yellow...Why?

Now, george (another_someone) has provided some excellent answers to questions about light and i think i now may understand why this is without actuall asking this question!

Would i be correct in thinking that, as george has previously stated, the light is infact yellow anyway. The reason it looks white is something because of the power of the battery...when the batteries are running down, they do not have the power to emit the full spectrum and so the light/beam given off looks the yellow that is actually is.

is my thinking about right?


 

another_someone

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Another question about light...
« Reply #1 on: 11/03/2007 23:10:39 »
It is vaguely like that.

The colour of light (if one is not talking about fluorescence) is a direct function of the temperature of the body that emits it.  As the battery reduces strength, the current through the bulb reduces, and so the temperature of the filament is reduced, and so the colour temperature of the emitted light is reduced (in this case, it means less blue in the light, and proportionately more yellow).
 

paul.fr

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Another question about light...
« Reply #2 on: 11/03/2007 23:14:44 »
It is vaguely like that.............


hurray for me. Thanks, George   ;D
 

Offline DoctorBeaver

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Another question about light...
« Reply #3 on: 13/03/2007 08:54:00 »
He's good, that George!  8)
 

The Naked Scientists Forum

Another question about light...
« Reply #3 on: 13/03/2007 08:54:00 »

 

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